Sodium Levels in Breast Cancer: Predicting Tumor Aggressiveness and Therapeutic Response

By: Victoria Kuhr, BA
Posted: Monday, June 27, 2022

According to William J. Brackenbury, MD, of the University of York, United Kingdom, and colleagues, noninvasive sodium MRI may improve the diagnosis of aggressive breast cancer, based on preclinical trial findings. Additionally, noninvasive sodium MRI may create a more sensitive noninvasive biomarker of treatment response compared with diffused-weighted imaging (DWI) alone. These findings were published in the British Journal of Cancer.

“There are currently only a handful of sodium MRI scanners across the country, but our study paves the way for them to be used as a new technique for diagnosing breast cancer, monitoring the success of treatments and improving survival rates for patients,” said Dr. Brackenbury in a University of York press release.

In this preclinical study, the mammary fat of 18 female Rag2^−/− Il2rg^−/− and Balb/c mice bearing orthotopic breast tumors (MDA-MB-231, EMT6, and 4T1) was surgically injected with cancerous cells. At 7 days after injection, the noninvasive sodium MRI revealed elevated sodium concentration in tumor regions compared with nontumor regions.

The tumors were randomly treated with the vehicle or the antineoplastic drug docetaxel. Treatment with docetaxel significantly reduced tumor growth, tumor volume, and noninvasive sodium signal in tumor regions compared with the control mice. However, docetaxel had no effect on the apparent diffusion coefficient.

The study authors also found combined noninvasive sodium MRI and DWI measurements increased classification accuracy of tumor versus nontumor regions compared with either parameter alone. The ex vivo assessment of isolated tumor slices confirmed elevated intracellular sodium content, whereas extracellular sodium content remained unchanged. Additionally, treatment with specific inward elevated sodium concentration conductance inhibitors (cariporide, eslicarbazepine acetate) did not affect the tumor sodium content. Nonetheless, effective treatment with docetaxel reduced tumor sodium concentration, whereas DWI measures were unchanged.

Disclosure: For full disclosures of the study authors, visit www.nature.com.

British Journal of Cancer

---